The present invention relates generally to sensing temperature, and particularly to sensing temperature at multiple points within a vessel.
Thermocouples are used in a variety of applications to sense temperature at a given location. A typical thermocouple comprises an external sheath and a pair of rod-shaped conductors disposed longitudinally within the sheath. Each conductor is of a dissimilar metallic material, and the two conductors are joined at a distal end within the sheath. An electrical insulation material also is packed about the rods within the sheath. The free ends of the conductors are connected to a detection instrument, such as a voltmeter, that measures the difference in potential created at the junction of the two metals. This difference in potential changes with temperature, thereby readily permitting the accurate detection of temperature at the junction point.
In some applications, multiple thermocouples have been combined to permit the sensing of temperature at a plurality of distinct locations or points. For example, sheaths are formed of differing lengths such that the junction point of the internal conductors for each sheath is located at a unique location. This combination of multiple sheaths and conductor pairs can be utilized to sense temperature at multiple locations in a given application.
The combination of thermocouples can be used, for instance, in high pressure reaction vessels. In certain applications, chemical reactions within the high pressure reaction vessels occur at different rates depending on temperature. Thus, it is desirable to sense the temperature within such reaction vessels to ensure the correct reaction occurs. In applications, such as the refining of petroleum, it can be important to closely monitor temperature at a variety of locations within the pressure vessel to ensure the proper reaction and proper produced material.
A temperature sensing technique is disclosed. In one embodiment of the technique, a vessel is provided for use in conducting, for example, high pressure chemical reactions. The technique also comprises at least one elongated sheath that extends into the vessel. A plurality of conductor pairs are disposed within each sheath and designed to detect temperatures at unique longitudinal locations along the elongated sheath. An insulation material is disposed about the conductor pairs within each elongated sheath. The invention also relates to a methodology for sensing temperatures at a variety of locations within a pressure vessel.